• Biomolecules & Therapeutics
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• 제17권2호
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• pp.113-124
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• 2009

Aging is a multifaceted biological process that affects all organs and organ systems of the body. This review provides an up-to-date analysis of this highly exciting, rapidly changing field of science. The aging process is largely under genetic control but is highly responsive to diverse environmental influences. The genes that control aging are those that are involved with cell maintenance, cell damage and repair. The environmental factors that accelerate aging are those that influence either damage of cellular macromolecules, or interfere with their repair. Prominent among these are chronic inflammation, chronic infection, some metallic chemicals, ultraviolet light, and others that heighten oxidative stress. Other environment factors slow the aging process. Included among these agents are resveratrol and vitamin D. In addition, dietary restriction and exercise have been found to extend human lifespan. The various mechanisms whereby all these agents exert their influence on aging include epigenetic modification, chromatin maintenance, protection of telomeres, and anti-oxidant defense, among others. The complex process of aging remains under continued, intense investigation.

• 한국펄프종이공학회:학술대회논문집
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• 한국펄프종이공학회 2011년도 춘계학술발표회 논문집
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• pp.339-347
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• 2011

This study was carried out in order to manufacture the high quality coated paper. High quality coated paper includes not only present state but also the state of the future. So in this study, acrylic-styrene emulsion which polymerized in laboratory was compared with SB(Styrene-butadiene) latex during thermal aging. The coated paper with three different formulations which controlled the dosage of acrylic-styrene emulsion were prepared. The coated paper were thermally aged at $105^{\circ}C$ for 18days and the optical properties were measured. Brightness, whiteness and CIE L value were higher during thermal aging with increasing amount of acrylic-styrene emulsion. CIE $a^*$ value was higher and CIE $b^*$ value decreased with increasing amount of acrylic-styrene emulsion. These results indicate that high quality coated paper which has anti -thermal aging property can be manufactured with acrylic-styrene emulsion.

• 한국철도학회논문집
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• 제8권2호
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• pp.188-194
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• 2005

Aging characteristics of glass fabric/phenolic composites for tilting train subjected to combined environmental aging factors were investigated. A 2.5KW accelerated aging tester with a xenon-arc lamp was used to provide environmental aging factors such as temperature, moisture, and ultraviolet. A series of aging tests were conducted up to 3000 hours and several types of specimens were prepared along the warp direction and the fill direction. Mechanical degradations for tensile, flexural, and shear properties were evaluated as a function of exposure times through a material testing system. Thermal analysis properties such as storage shear modulus, loss shear modulus, and tan 3 were measured through a dynamic mechanical analyzer. Finally exposed surfaces of the composites were examined using a scanning electron microscope. According to the experimental results, mechanical properties and thermal analysis properties of glass fabric/phenolic composites were found to be slightly degraded as a function of exposure times due to combined environmental effects.

• Earthquakes and Structures
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• 제6권2호
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• pp.127-140
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• 2014

Laminated rubber bearing is very popular base isolation of earthquake engineering pertaining to the passive structural vibration control technologies. Rubber used in fabricating NRB and LRB can be easily attacked by various environmental factors such as oxygen, heat, light, dynamic strain, and organic liquids. Among these factors, this study carried out thermal aging test to investigate the effect of thermal aging on the mechanical properties of laminated rubber bearings in accelerated exposure condition of $70^{\circ}C$ temperature for 168 hours. The compressive-shear test was carried out to identify the variation of compressive and shear properties of the rubber bearings before and after thermal aging. In contrast to tensile strength and elongation tests, the hardness of rubber materials showed the increasing tendency dependent on exposure temperature and period. Based on the test results, the property changes of rubber bearing mainly aged by heat are quantitatively presented.

• 성인간호학회지
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• 제17권1호
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• pp.128-138
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• 2005

Purpose: As population of elderly people continues to grow, successful aging has risen to the top of the nursing science agenda. The successful aging includes maintenance of the cognitive and physical functions, as well as emotional well-beings. This study was carried out to evaluate effects of the environmental enrichments on cognition of institutionalized elderly. Method: The population was selected among the elderly aging over 65 residing at two of institutions. A quasi experimental design was used with non-equivalent control group. Study subjects were thirteen for each group. For the experimental group, physical, social and symbolic environmental enrichment program was provided for six weeks. The data were analyzed by repeated measure ANOVA and repeated measure ANCOVA using SPSS Win 11.0. Result: Compared to control group, the experimental group showed a significant difference on DSF(F=3.29, p=.046), and TMTA(F=4.76, p=.013) of cognitive function, and depression (F=5.56, p=.007) of emotional distress after 1 and 12 weeks of environmental enrichment program. Conclusion: Findings indicate that physical, social, and symbolic environmental enrichment was effective to partially prevent from cognitive decline, and to decrease emotional distress of elderly. As a nursing intervention, environmental enrichment program for elderly should be expanded for nursing practice to promote healthy aging and to offer support to the growing population of elderly. Further research should be conducted to evaluate the effect on the community elderly.

• 한국응용과학기술학회지
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• 제38권6호
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• pp.1616-1626
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• 2021

본 연구는 액티브 시니어 골프참여자를 대상으로 지각된 환경적요인과 주관적 건강 및 활동적 노화에는 어떠한 관계가 있는지 규명하는데 목적이 있다. 본 연구의 목적을 달성하기 위하여 SPSS(Statistical Package for the Social Sciences) 18.0과 AMOS(Analysis of Moment Structures) 18.0을 이용하여 빈도분석, 확인적 요인분석, 신뢰도분석과 상관관계분석을 실시하였고 모형을 설정한 뒤 구조방적식모형(Structural Equation Modeling)을 통하여 변인 간의 인과적 관계를 규명하였다. 이상과 같은 연구방법과 연구모형 검증을 기초로 하여 본 연구에서 도출된 결과는 다음과 같다. 첫째, 지각된 환경적요인은 활동적 노화에 정적인 영향을 미치는 것으로 나타났다. 둘째, 활동적 노화는 주관적 건강에 정적인 영향을 미치는 것으로 나타났다. 셋째, 지각된 환경적요인은 주관적 건강에 정적인 영향을 미치는 것으로 나타났다. 넷째, 지각된 환경적요인과 주관적 건강의 관계에서 활동적 노화는 매개하는 것으로 나타났다.

• 펄프종이기술
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• 제44권3호
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• pp.15-21
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• 2012

The optimum dewaxing ratio in dewaxing treatment by the heat and pressure method was investigated by considering aging stability of dewaxed Hanji. Commercial Hanji was coated with beeswax and thermally aged at $150^{\circ}C$ for 24 hours. Then it was dewaxed using the laboratory sheet press equipped with hot plates on both top and bottom sides. Dewaxing ratio was controlled by pressing temperature and time. Four type of dewaxed Hanji samples with different dewaxing ratio were prepared and thermally aged at $150^{\circ}C$. Then the aging stability of dewaxed Hanji samples was evaluated in terms of optical and strength properties. It was found that the aging stability of dewaxed Hanji was superior with higher dewaxing ratio. The result concluded that, in the aspect of aging stability, the coated beeswax in beeswax-treated Hanji shall be completely removed if the coated wax would be dewaxed.

• 펄프종이기술
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• 제43권1호
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• pp.11-16
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• 2011

This study was carried out in order to elucidate the effect of latex dosage and properties on aging behavior of coated paper. The coated paper with five different coating formulations were prepared and also four different latices were used. The coated paper were thermally aged at $105^{\circ}C$ for 14 days and the optical properties were measured. Increasing latex content increased the magnitude of reduction in brightness and whiteness. In addition, the variations in CIE a$^*b^*$ were larger with increasing latex dosage. Latex which has the lower gel content and the higher Tg showed the higher reduction in brightness and whiteness and much variation in CIE a$^*b^*$. However the particle size of latex didn't affect to thermal behavior of coated paper. These results indicate that latex which has higher Tg and lower gel content is the one of the main factors affecting aging behavior of coated paper.

• 한국지하수토양환경학회지:지하수토양환경
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• 제21권3호
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• pp.82-87
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• 2016

This study investigates effects of an aging period on arsenic (As) chemical forms in soils and phytotoxicity using artificially As-contaminated soils with a range of As concentrations (0-300 mg/kg) and aging periods (0 and 3 months). A sequential extraction procedure showed that the increasing As concentration in soils increased the ratio of non-specifically and specifically bound As, which are known to be bioavailable. This resulted in increasing As uptake by tomatoes with increasing As concentration (R²=0.87 for exponential fitting); however, the seed germination was not sensitive to the As concentrations of the soil samples. The seed germination was also statistically similar in the soils with 75 and 150 mg-As/kg regardless of the aging period. The time taken until the seed germination (i.e., lag phase), on the other hand, decreased from 10 d to 3 d with aging for 3 months. This can be attributed to the decreased amount of bioavailable As with aging. Overall, this study shows that when the toxic effects of the As-contaminated soils are assessed using tomato plants, it is better to use more sensitive methods than seed germination such as the As accumulation or the lag phase for seed germination.

• 전기학회논문지
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• 제64권10호
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• pp.1411-1417
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• 2015

The installation of PV system to the power distribution system is being increased as one of solutions for environmental pollution and energy crisis. However, the efficiency of PV system is getting decreased because of the aging phenomenon and several operation obstacles. Therefore, The technology development of aging diagnosis of PV modules are required in order to improve operation performance of PV modules. This paper proposes evaluation algorithm for aging state in PV modules by using the electrical characteristics of PV modules and environmental factors. And also, this paper presents a operation evaluation system of PV modules based on the proposed aging diagnosis algorithm of PV modules. From the simulation results of proposed evaluation system, it is confirmed that the proposed algorithm is a useful tool for aging diagnosis of PV systems.